Black tree kangaroo description

The black tree kangaroo has the dubious honour of being one of the ‘tastier’ marsupials discovered by early Dutch explorers on the island of New Guinea (5). The first part of its scientific name, ‘dendron’, means tree in Greek while ‘lagus’ means hare (5)(6); it is thought that it was given the ‘lagus’ part of this name due to its gastronomic similarity to hare rather than for its hopping style of locomotion (5)(7). Sadly, this name also serves as a potent reminder of one of the main threats to this exceptional creature: hunting by humans for food (1)(5)(8).

The black tree kangaroo is easily recognised by its long, tufted ears which are unique amongst tree kangaroo species (6). Lustrous, long, black fur covers the back and tail, while the fur on the underside is coffee-coloured. Its distinctive face is more brown, with white, or sometimes red, cheeks and a white throat, explaining why it is also commonly called the white-throated tree kangaroo (5)(6). The fur on top of the shoulders grows in a spiral pattern or whorl, which is thought to protect the face by channelling rainwater away from the head (5). As a member of the short-footed group of tree kangaroos (6), the black tree kangaroo is well adapted to an arboreal lifestyle. It has sturdier arms and shorter, wider feet than its ground-dwelling relatives with roughened pads for gripping, well-developed curved claws on its front paws to aid climbing, and a long, white-tipped tail which acts as a counter-balance while in the trees (5)(6).

Related species

Black tree kangaroo biology

Unfortunately, since its discovery in the early 19th century very little information has been gathered about this enchanting species. It is known to be mostly solitary and nocturnal, emerging after dark to feed on its preferred food of leaves and fruit (5)(6). Some reports suggest that a large proportion of the black tree kangaroo’s diet may consist of fruit; this would make them unique amongst their tree kangaroo relatives who are predominantly foliovores (leaf-eaters) (6). All tree kangaroos leave the safety of the trees at some point to forage on the ground, but the amount of time spent on the ground tends to vary dramatically between species (5). While they move through the treetops with superb agility - with some tree kangaroo species being able to drop to the forest floor from heights of 7 to 15 metres without injury (2)(7) - once on the ground their movements can be slow and clumsy, travelling with a bipedal (two-footed) hopping motion reminiscent of the larger, ground-dwelling kangaroos (9).

It is probable that the black tree kangaroo, like other tree kangaroos, can mate throughout the year, giving birth to a single, under-developed joey after a gestation period of around 32 days (2). The tiny newborn is vulnerable without fur or sight, but has well-developed forelimbs that enable it to climb up its mother’s fur into the protective environment of her pouch (10). The joey will continue to grow and develop within the warm, safe pouch for a further 300 days or more, gaining all the nutrients it requires from its mother’s milk (2). Tree kangaroos reach sexual maturity at around two years of age and can live as long as 20 years in captivity (3).

Black tree kangaroo range

The black tree kangaroo is found exclusively in the north-western region of the island of New Guinea, Indonesia, where it is restricted to the Vogelkop or “Bird’s Head” peninsula (so-called because of its resemblance to a bird’s head) and the Fak Fak peninsula (1)(8).

Species with a similar range

Black tree kangaroo habitat

Historical reports indicate that this species once had an extensive range from lowland forest at sea-level to high mountainous rainforest (1)(6). However, due to the threats it faces at lower elevations, it is today only found between 1,000 and 2,500 metres above sea level, in tropical forest (1).

Black tree kangaroo status

Black tree kangaroo threats

The black tree kangaroo is currently under threat from hunting by local people for its meat and has been classified as Vulnerable to extinction on the IUCN Red List due to the fact that its population numbers have declined by at least 30 percent in the last 30 years and continue to do so (1). This reduction in population is evident by its disappearance from the more densely populated areas of the Vogelkop Peninsula, within the Arfak montane forests for example, so that its range is now limited to areas with little or no human presence (1)(6)(8).

Hunting pressure is unfortunately not the only threat faced by this beautiful marsupial. Increased logging and forest clearance for agricultural purposes has meant that the black tree kangaroo has lost a considerable part of its habitat over the last 60 to 70 years, with a resultant decline in its numbers (1)(8).

Black tree kangaroo conservation

Although there are no specific conservation measures in place for this species, the region in which they are found contains ten protected areas which make up 52 percent of the Vogelkop montane rainforests (8). When compared to the rest of New Guinea, these forests are in relatively pristine condition and with continued conservation efforts from organisations such as WWF and the Tenkile Conservation Alliance (established primarily for the Scott’s and golden-mantled tree kangaroos) (11), it is hoped that increased awareness and protection can be given to these enigmatic and captivating marsupials.

Glossary

Arboreal

An animal which lives or spends a large amount of time in trees.

Gestation

The state of being pregnant; the period from conception to birth.

Marsupial

A diverse group of mammals characterised by their reproduction, in which gestation is very short, and the female typically has a pouch (marsupium) in which the young are raised. When born, the tiny young crawls to the mother’s teats, where it attaches and stays for a variable amount of time, whilst it continues to develop. Marsupials also differ from placental mammals in their dentition.

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